1. Field of the Invention
This invention relates to a method for preparing an elastic roller such as pressure roller, cleaning roller and platen roller, etc. and a molding device therefor.
2. Related Background Art
In the prior art, when a roller is molded with a mold cavity in which lid members at both end openings of the cylindrical hole are used for holding a core metal member shaped in a shaft concentrically with the cylindrical hole within a molding cavity having a cylindrical hole extending therethrough, the material flows into the gaps between the molding cavity having cylindrical holes at the both peripheral end portions of the roller and the lid members, and also into the gaps of the core metal holding portions of the lid members, thereby forming burrs. When such burrs exist, there is the fear that the roller may entangle in the burrs when it is mounted on the bearing, whereby it may no longer become rotatable. For this reason, a deburring step for removing such burrs is required, which requires very cumbersome labor. Accordingly, it may be conceivable to use a mold cavity which can be precisely fitted without forming burrs, but when a liquid starting material is used, inflow will occur even through small gaps, thereby forming burrs which can only be removed with difficulty. Also, if the peripheral end portions are completely sealed, air does not escape, whereby there is the problem that air remains at the end portion of the molded roller. Accordingly, it is important to develop a new molding method which prevents air remaining in the molded roller and also requires no burr removal post-treatment for the end portions.